Allegedly, the Mavericks offered Caron Butler's corpse and expiring contract and the 2011 first-round pick for the Pistons' Tayshaun Prince.
Prince, also, has an expiring deal. The contracts are almost identical. The Pistons would essentially get a bad draft pick (in the 20s, which you could make work, but isn't great).
I don't know why the Pistons wouldn't bite other than not pissing Prince off and possibly re-signing him in the off-season.
The Mavericks also went after the Nuggets' J.R. Smith, but I don't think the Nuggets were into any more moves unless someone knocked their socks off.
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Everyone is seemingly in too far in love with Caron Butler. They typical issuance is that "He's not a superstar, but he's a piece to the puzzle."
The NBA is no longer a league where you have a superstar and pieces. You need two or three superstars and good, respectable role players.
The Mavericks have one superstar. A couple of pieces. And some junk.